Zimbra Desktop query

Hi Gents,

Since my legacy emailing system was simple POP/Postfix/squirrel stuff, I soon will be migrating over the zimbra. Now while migrating I have already asked user to convert the mails into PST or download all those mails from server and store it in PST so that I can easily upload using PST Import.

I am planning to provide them an zimbra desktop and would like to know below points before actually I commence the work.

once the PSTs are migrated I am gonna ask user to create local folder and move their mails over there. Now,

1] What format does zimbra desktop store the emails if those are moved to local folder?

2] Can those directly be converted into whatever format zimbra uses and have it moved to users folder?